Existenz, Inception, The Matrix and Iain Bank’s Surface Detail all touch on the question of how many tiers virtual realities might conceivably comprise, on where the boundary between virtual reality and alternative reality lies, and at what point these become indistinguishable from our own assumed reality. It is a question that Philip K. Dick also asked in novel after novel. What is the real – and how do we know for sure?

Though this story was written for fun, the questions it raises are questions which our electronic civilisation must increasingly confront.